Factors Influencing Postoperative Intraocular Lens Tilt And Decentration Of A New Hydrophobic Acrylic Toric Intraocular Lens

To investigate possible factors influencing the decentration and tilt of a new hydrophobic acrylic toric intraocular lens. 

This single center, prospective, interventional clinical trial was conducted at the Department of Ophthalmology and Optometry at the Medical University of Vienna.

In total 130 eyes of 82 patients received a Clareon (CNW0T3-9) hydrophobic toric acrylic intraocular lens (IOL). Tilt, decentration, aqueous depth (AQD) and lens thickness (LT) were determined preoperatively, at 1 week (1w) and 6 months (6m) postoperatively using an anterior segment OCT (AS-OCT) Casia2 (Tomey Corporation, Nagoya, Japan). Tilt and decentration of the IOL were calculated using the corneal vertex as a reference point. Axial eye length (AXL) was assessed with the IOL Master 700 (Zeiss, Jena, Germany). The correlations were calculated using Spearman's rho. Throughout the analysis, p-values < 0.05 were deemed statistically significant.

After 6 months, the tilt of the IOL was 5.8° ± 1.6° and the decentration of the IOL was 0.25 mm ± 0.15 mm. Tilt of the IOL after 6 months showed a significant negative correlation with AXL (r= -0.38; p= <0.001). Correspondingly, tilt was negatively correlated with the preoperative AQD (r= -0.20; p= 0.03). Significant correlations were found between preoperative and postoperative tilt (r= 0.92;p= <0.001), and decentration (r= 0.27;p= <0.001) at 6m. No correlations were found between decentration at 6 months and AXL (r= -0.02;p= 0.86), LT (r= -0.03;p= 0.724) and preoperative AQD (r= -0.11;p= 0.24). 

A shorter axial eye length and a smaller anterior chamber increased tilt of the IOL. Both, tilt and decentration of the phakic lens, were significantly correlated with postoperative tilt and decentration. Decentration of the crystalline lens correlated more with tilt of the IOL than with decentration of the IOL after 6 months postoperatively.